Metformin, i.e. N,N-dimethylimidocarbonimide diamide, is a known compound approved by the U.S. Food and Drug Administration for the therapeutic treatment of diabetes. The compound and its preparation are disclosed, for example, in U.S. Pat. No. 3,174,901, issued May 23, 1965. It is known that metformin is effective in the treatment of type 2 diabetes, otherwise known as non-insulin-dependent diabetes mellitus (NIDDM). Metformin was the first oral antidiabetic agent introduced that is chemically and pharmacologically unrelated to the oral sulfonylurea diabetic agents, such as tolbutamide.
A statement used to describe metformin in the Informed Drug Guide is that proof that it has an advantageous effect on the prognosis of diabetes (complications, mortality) does not exist. In accordance with the present invention, it has unexpectedly been found that metformin does exert an effect against long term complications that are frequently associated with type 2 diabetes. This effect, not previously known, is quite possibly due to a mechanism of activity separate and distinct from its hypoglycemic activity.
The invention relates to the use of metformin in a dosage regimen significantly higher than its established therapeutic antidiabetic dosage as a treatment/preventative against long-term complications of type 2 diabetes as might normally occur during extended therapy of the disease. This activity would typically not manifest itself during the administration of metformin in the generally prescribed therapeutic dosage ranges.